POS0922 DIFFERENTIAL DIAGNOSIS OF FOCAL IMMUNOGLOBULIN G4-RELATED SIALADENITIS AND BENIGN SALIVARY MASSES: THE VALUE OF CONTRAST-ENHANCED ULTRASOUND
Authors: Y. Xin, S. Zhang, F. Liu, J. Zhu
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Immunoglobulin G4 related disease (IgG4-RD) is a newly recognized immune-mediated fibroinflammatory disease characterized by involvement of multiple organs, among which salivary gland is one of the most commonly involved sites. Immunoglobulin G4-related Sialadenitis (IgG4-RS) presents itself as focal or diffuse lesions, of which focal lesions are difficult to differentiate from salivary gland masses <sup>[1]</sup>, especially benign masses with a high clinical incidence. Differential diagnosis of both sets of disorders has significant clinical implications due to different treatment modalities. <h3>Objectives</h3> The aim of this study was to clarify the effectiveness of contrast-enhanced ultrasound (CEUS) in differential diagnosis of focal IgG4-RS and benign salivary masses. <h3>Methods</h3> We retrospectively included 13 patients with diagnosis of focal IgG4-RS according to the Comprehensive Diagnostic Criteria for IgG4-RD (20 foci) and 32 patients with pathologically confirmed benign salivary masses (32 foci). Ultrasonography [grey scale (GS), color Doppler flow imaging (CDFI) and CEUS] of the bilateral parotid and submandibular glands were performed by two experienced radiologists in all patients. We compared the characteristics of ultrasonography and determined the diagnostic value for differentiating between focal IgG4-RS and benign salivary masses. <h3>Results</h3> Of the 13 focal IgG4-RS patients, 7 were female and mean age was 57.46 (± 9.90) years, which was older than that of patients with benign salivary masses (41.03 ± 13.52 years) (<i>p</i> &lt; 0.001). Focal IgG4-RS patients were more frequently presented with gland enlargement and elevated serum levels of IgG4 and IgE (<i>p</i> &lt; 0.001). These two groups of patients showed localized hypoechoic masses on gray-scale ultrasound, with homogeneous or heterogeneous internal echo, while focal IgG4-RS may have unclear boundaries. CDFI revealed more abundant blood flow signals of patients with IgG4-RS, mostly grade II-III. Compared with benign salivary masses, patients with focal IgG4-RS more often showed iso-enhancement, blurred enhancement margins, whereas unenhanced area was less frequently present. The detail ultrasonography characteristics of patients were compared in Table 1. The AUC of CEUS and conventional ultrasound for differentiating focal IgG4-RS and benign salivary masses were 0.973 and 0.891, respectively, of which CEUS is superior to conventional ultrasound (<i>p</i> &lt; 0.05). <h3>Conclusion</h3> CEUS was remarkably effective in differentiating focal IgG4-RS and benign salivary masses, its discriminatory value was superior to conventional ultrasound. The diagnostic accuracy can be more improved by effectively combing clinical data and laboratory findings. <h3>Reference</h3> [1]Stone JH, Zen Y, Deshpande V. IgG4-related disease. N Engl J Med. 2012; 366:539-51. <h3>Acknowledgements</h3> This study was supported by the National Natural Science Foundation of China (No. 82071930). <h3>Disclosure of Interests</h3> None Declared.